Process for producing motor fuel by alkylation



July 19, 1949.

M. P. MATUSZAK PROCESS FOR PRODUCING MOTOR FUEL BY ALKYLAT'ION FiledOct. 8, 1947 HOlV-HVdBS ISOBUTANE EOLDVHH ETHANE IOI FIG. 3

3 Sheets-Sheet 5 COOhER "fl-" M. P. MATUSZAK ATTORNEYS Patented July 19,1949 PROCESS FOR PRODUCING MOTOR FUEL I BY ALKYLATION Maryan P.Matuszak, Bartlesville, kla., assignor to Phillips Petroleum Company, acorporation of Delaware V Application October 8, 1947, Serial No.778,607 7 18 Claims.

. 1 This invention relates to an alkylation process. In one embodimentit relates to a method of removing reaction "by-products from theeffluent of a catalytic alkylation process. In another embodiment itrelates to a method of removing organically combined halogen (hereindesignated organic halogen), such as fluorine or chlorine from paraffinhydrocarbon materials contaminated therewith. In another embodiment itrelates to an improved. method of alkylating a low-boiling paraflin,usually an isoparaffln, with an alkylating agent, usually a low boilingolefin, to make a higher-boiling parafiin (known in the art as alkylate)which is useful as a high octane base or blending stock for motor andaviation fuel. 7

This invention is a continuation-in-part of my co-pending applicationSerial No. 602,247, filed June 29, 1945, and now Patent No. 2,432,482.In one embodiment, it comprises, in combination, catalytic alkylation ofa parafin with an alkylating agent in a first alkylation zone,subsequent addition of an excess of a relatively easily alkylatablecompound of the type of benzene and catalytic alkylation thereof in asecond alkylation zone with icy-products formed in the first alkylationzone, subsequent catalytic alkylationof the excess added easilyalkyltable compound with added olefin in a third alkylation zone, andisolation of resultant composite alkylate boiling in the motor-fuelrange as the main product of the process.

The principal object of this invention is to provide an improvedalkylation process.

Another object is to provide an improved method of removing reactionby-products contained in the effluent material from a catalyticalkylation process.

Another object is to provide an improved method of removing organichalogen from parafiin hydrocarbon materials containing the same.

Another object is to provide an improved method of removing organicsulfates from parafiin hydrocarbon materials containing the same.

Another object is to provide an improved method of removing fluorinefrom paraifin hydrocarbon material contaminated therewith, such asalkylate made by alkylationof an isoparaifin with an olefin by means ofhydrofluoric acid as a catalyst.

Numerous other objects will be obvious to one skilled in the art fromthe accompanying disclosure and discussion.

Ordinarily, the parafiin is an isoparafiin, selected vbecause of itsrelatively high reactivity,

V and expense.

and it is preferably isobutane, primarily because of its availability atrelatively low cost. V The alkylating agent is usually one or .moreolefins, but in some applications it may be oneor more olefinderivatives, such "as'alcoholaalkyl halides, or the like. Thealkylationcatalys t may be any that is effective for promotingalkylation of the selected paraffin withthe' selected alkylating agentsuch as anhydrous hydrogen fluoride, sulfuric acid or others.Hydrofluorioacid is preferred for alkylation of'anisoparafiin witholefins heavier than ethylene or'with polar nonprimary alkyl compounds.When'ethylene or a primary alkyl compound is the alkylating agent, thecatalyst may be advantageouslya mixture of hydrofluoric acid andjboronfluoride; this catalyst may also be used in alkylation of normalparafiins. Ordinarily, however, when a normal paraffin is beingalkylated, or when the alkylat ing agent is ethylene; the preferredcatalyst is one comprising aluminum chloride or bromide, promoted withan alkyl halide or a hydrogen halide, usually hydrogen chloride,"as inthe com mercial manufacture of diisopropyl and other hydrocarbons fromisobutaneand ethylene.

In the paraflin-alkylation step, conditionsfor which depend upontheparticular reactants and catalyst and may be selected in accordance'withknowledge available to the art, some undesired by-products are formed,resultin in objectionable consumption of reactants or catalyst, or both,and in objectionable contamination of the product and the survivingreactants. The principal by-products are compounds or complexes formedfrom hydrocarbons and alkylation catalyst, polymers formed fromalkylating agent, and heavy alkylates that boil above the desiredmotor-fuel range} The proportions of these undesired by-products, and,even their identities. depend considerablyupon the particular materialsand the particular conditions present, but their formation has' longbeen recognized for every catalytic parafiin-alkylation process nomatter whether the catalyst comprises hydrofiuoric acid, aluminumchloride, sulfuric acid, or any of many less widely used alkylationcatalysts.

In the past, little has been done to counteract the formation of thesevarious'undesired byproducts except to remove and withdraw the mostobjectionable ones at considerable trouble For example, when ahalogencontaining catalyst is used, a small proportion of organichalogen appears in the alkylate and in the surviving reactantajandthe'seflmaterials in consequence may be subjected to a treating stepdesigned to remove the organic halogen, such as contacting at a suitabletemperature with solid metal oxides or other materials that adsorb theorganic halogen compounds, or catalyticall-y split out the halogen asthe hydrogen halide, or react to form metal halides. Treating withbauxite or similar material ex emplifies such a treating step forremoving a halogen like chlorine or fluorine. When fluorine is thehalogen, considerable diiiiculty arises because of the formation ofsilicon tetraiiuoride from silica present in the bauxite or similarcontacting agent; the silicon tetrafiuoride is carried along in thehydrocarbon stream and subsequently causes trouble by becominghydrolyzed by moisture, forming silicic acid that plugs equipment andnecessitates expensive shutdowns for removal. Eliminating or minimizingthe formation oi the organic halogen compounds is obviously highlydesirable Similarly, coun teracting the formations: other undesired byproducts is highly desirable.

In the process ,of this invention, substantial counteracting of theformation of lay-products is obtained by fmix'injgiwith the alkylationreaction mixture, after the Ip'araflin alkylation is substantiallycompleted, an "excess of a relatively easily alkylatable compound.compound, in the presence of the alkylation catalyst, undergoesalkylation with any surviving alkylating agent added as such and withvarious by-products of the paladin alkylation. Afprocess utilizingsomewhat similar alkyla'tion and directed primarily to reduction bforganic halogen, has been described in co-pending application Serial No.602,247,1'filed June 29, '194 5,'a1l1dnow Patent No. 2,432,482. In theprocess or the present invention, in partial contrast, a relativelylarger proportion "of easily alkylatable compound is required, to react"primarily with the by-products other than, for example, organic halogencompounds'; -furthe'ririoi e, the present process is broader than thatof my above mentioned copending application in that-it may be applied to1 halogen-"free systems, although reduction of organic halogen is'no'tto be excluded in particular applications. When organic halogencompounds are present, the organic halogen 'is liberated as hydrogenhalide, which becomes available for reuse; simultaneously, the addedeasily alkylatable compound bec'o'm''s alkylated. Similar reactionsoccur with other catalyst-hydrocarbon compounds or complexes; forexample,v when suliuric acid is the catalyst, 'by-product alkyl sulfatesor 'bi'sulfates alkylate'the added compound with'regeheiationdf'sulfuric acid. In somewhat analogous ta'sh'io'n, other by-productsare consumed in alkyl'atin'gthe added easily alkylatable compound; suchmaterials as polymers, so-called acid-solubleoil'formed in hydrofluoricacid and low-boiling easily alkylatable aromatic hydrocarbons that maybe formed, for example, in cracking steps generally constitutes a highlysatisfactory compound and may be preferred because of ready availabilityat low cost. Especially advantageous is such a material when it isalready being used for blending with motor-fuel hydrocarbons produced byparaffin alkylation, for then there is substantially no additional costfor o the added easily alkylatable compound. However,

other compounds may be suitably utilizable in particular applications ofthe process. Among compounds that may be used in this way are iuran,phenol, pyrrol, thiophene, and similar alkylatable compounds that may becharacterized as having at least two conjugated double bonds in a ring;but usually benzene or other low-boiling aromatic hydrocarbon, such astoluene, is preferable because of the absence of an element other thancarbon and hydrogen. 7

Intimate mixing of the added compound with the paraiiin-alkylationreaction mixture, including an alkylation catalyst, is essential. Themixing period required depends upon the added compound, upon thereactivity of the various paraffinalkylation by-products, and upon theactivity of the catalyst, but a suitable period, which is ordinarilymeasurable in minutes, usually in the range of 1 to 20 minutes, can bereadily found by trial for any specific application. In general, theconditions are simil'art'o those in the .para'ffinalkylation step, sothat heating, cooling, 'or other special conditioning is not necessarythough such conditioning may be advantageous in particular 7applications. In some aprilicationsgspecial mixing means may beunnecessary, provided that the added compound is adequatelydis'persedinto the reaction mixture eflluerit from the'paraffinalkylation zone, as by ejection from one or more jets; in suchapplications, substantial -alkylation of the added compound occursduring passage :of the reaction mixture to the next step, especiallywhen baiiies are provided to maintain intimate mixing during thispassage. Preferably, the added compound should not be present within theparafiin -alkylation zone, wherein it would compete undesirably with theparaffin "for the alkylatlng agent ied to this zone, "but traces addedin recycled material may be economically permissible.

In one embodiment, the by-product-alkylation step and the precedingparafiin-alkylation step may be conducted with two separate bodies ofcatalyst. Although the two bodies may be of diiierent catalysts, such ashydrofluoric acid for the paramn-alkylation step and sulfuric acid forthe by-product-alkylation step, it is usually preferable to have both ofone catalyst. -Byuse of the two separate bodies of catalyst,anycarryover, to the paraffin alkylationstep, of surviving addedcompound (a. g., benzene) in solution in recycled catalyst is avoided.Such carry-over is disadvantageous to the extent that the added compoundcompetes with the parafiin -'for the olefin or other alkylatin'g agentfed to the-process. This application requires an intermediate-separation step for separating the reaction mixture eiiluent from theparaffin-a'l-kylation step into a hydrocarbon phase, which is passed tothe byproduct-alkylation step, and into'acatalystphase, which isrecycled to the first step or is passed in part to a purification orcatalyst-recovery system.

Regardless of whether or not a separate -body of catalyst hasbeen used,the reaction mixture efliuent from the by-product "alkylation step ispassed to a final alkylation step, wherein at least part of the excessadded compound is alkylated with an added olefin that is consumed sorapidly under the prevailing conditions that any objectionableby-products are negligible. When, as is preferred, the excess addedcompound is benzene, the olefin added in this step is preferablyethylenefree and is most preferably propylene, inasmuch as thisparticular olefin has a relatively small tendency to form objectionableby-products and inasmuch as the resulting alkylated benzene is mainlycumene, which is an especially desirable motor-fuel ingredient. Thisadvantageous conversion of excess benzene to cumene results in anincreased yield and in an improved quality of the motor fuel formed bythe process.

The reaction mixture efiluent from the final alkylation step is passedto a settler for separation into hydrocarbon and catalyst phases. Thecatalyst phase is recycled to its point of original introduction intothe system or is in part passed to a catalyst purification or recoverystep. The hydrocarbon phase is freed from traces of catalyst and isfractionated into desired product, byproduct, and recycle fractions. Ifthe same catalyst is used in all alkylation steps then only one catalystregeneration system is necessary.

It will be appreciated that the final alkylation step eliminates inlarge measure the benzene or other relatively easily alkylatablecompound from the catalyst phase. By proper adjustment of the proportionof olefin added to this step, substantially no excess or unconsumedbenzene remains in the catalyst, which consequently is renderedsubstantially unobjectionable for use in the paraffin-alkylation step.Although use of one and the same body of catalyst for all alkylationsteps presents a, need for relatively fine control, it is advantageouswhen equipment is limited or unobtainable in the amount required for useof two separate bodies of catalyst or when the scale of operationjustifies it for economical reasons. Accordingly, such use of one bodyof catalyst for all alkylation steps is considered within the scope ofthis invention.

In the accompanying drawing Figure 1, Figure 2, Figure 3 and Figure 4each illustrates one embodiment of my invention. Referring to Figure 1of the drawing an alkylatable parafiin hydrocarbon is passed throughline H to reactor l3. An alkylatin agent, such as an olefin, isintroduced into reactor l3 through line l2 by way of line H. Analkylation catalyst, for example, an anhydrous hydrofluoric acid isintroduced into reactor l3 by way of line M-. The contents of reactor l3are maintained under alkylation conditions and are mixed by any suitablemeans, such as a mechanical stirrer, which is not shown. The reactionmixture eiiiuent from reactor l3 passes through line IE to reactor l8.An easily alkylatable cyclic organic compound, such as benzene, isintroduced into reactor [8 by way of lines I! and H5. The contents ofreactor ll are maintained under alkylation conditions and are mixed byany suitable means not shown. The reaction mixture effluent from reactor[8 passes through line l9 to reactor 22. An alkylating agent, such as anolefin, is introduced into reactor 22 by way of lines 2| and I9. Thecontents of reactor 22 are maintained under alkylating conditions andare mixed by any suitable means not shown. If desirable, at least aportion of the reaction mixture efliuent from reactor I8 may bypassreactor 22 by way of line 20 and enter separater 24 by Way of line 23.The'reaction mixture eiliuent from reactor 22 passes through line 23 toseparator 24 where the reaction mixture is separated by gravity into ahydrocarbon phase and a catalyst phase. The catalyst phase is recycledto reactor i3 by way of lines 21, 28 and M and is reused in each of thereactors, namely l3, l8 and 22. However, at least a portion of saidcatalyst may be withdrawn from line 21 and passed through line 31 tocatalyst purification unit 38 where the catalyst is regenerated. Thepurified catalyst is returned to the system through lines. 39, 28 and Hito reactor l3. If desirable, however, at least a portion of the purifiedcatalyst may be withdrawn from the system through line ll. Thehydrocarbon phase from separator 24 passes through line 26 tofractionation unit 3 l. The unreacted parafiin in the original feed isrecycled through lines 32 and H to reactor l3. However, at least aportion of this paratin recycle material may be removed from the systemthrough line 32A. The product coming within the motor fuel boiling rangeis removed from the fractionation unit 3! through line 33. Any catalystthat might have been carried over from separator 24 to fractionationunit 3! is recycled through lines 34, 28 and It to reactor it. The heavymaterial boiling above the motor fuel boiling range is removed fromfractionation unit 3| through line 36.

. Referring to Figure 2 of the drawing an alkylatable paraffinhydrocarbon is passed through line 5| to reactor 53. An alkylatingagent, such as an olefin, is introduced into reactor 53 by way of lines52 and 5!. An alkylation catalyst, such as sulfuric acid, is introducedinto reactor 53 by way of line 54. The contents of reactor 53 aremaintained under alkylation conditions and are mixed by any suitablemeans not shown. The reaction mixture effluent from reactor 53 is passedthrough line 56 to separator 51 where the mixture is separated by ravityinto a hydrocarbon phase and a catalyst phase. The catalyst phase isrecycled through lines 58 and 54 to reactor 53. However, if desirable,at least a portion of the catalyst phase may be passed from line 58through line 83 to catalyst purification unit 86 where it is purified.The hydrocarbon phase from separator 51 passes through line 59 toreactor 62. An easily alkylatable cyclic organic compound, such asbenzene, is introduced into reactor 62 by way of lines 6| and 59. Asuitable alkylation catalyst, such as sulfuric acid, is introduced intoreactor 62 by way of line 63. The contents of reactor 62 are maintainedunder alkylation conditions and are mixed by any suitable means notshown. The reaction mixture efiiuent from reactor 62 is passed throughline 64 to reactor 61. An alkylating agent, such as an olefin, isintroduced into reactor 61 by way of lines 66 and 64. The resultingreaction mixture is maintained under alkylating conditions in reactor 61and is mixed by any suitable means not shown. At least a portion of thereaction mixture efiluent from reactor 62 may by-pass reactor 61 and beintroduced directly into separator 63 by way of lines H and 68. Thereaction mixture efiiuent from reactor 61 is passed through line 68 toseparator 59 where it is separated by gravity into a hydrocarbon phaseand a catalyst phase. At least a portion of the catalyst phase may berecycled through lines 12,13 and 63 to reactor 62. Also, at least aportion of the catalyst phase may pass through line E2 to catalystpurification unit 86. The hydrocarbon effluent from separator 69 passesthrough line 14 to fractionation unit I6.

The unreacted parafiin contained in the original feed is removed fromfractionation unit 16 and recycled through lines I! and EI to reactor53. However, at least a portion of the recycled paraffin may be removed,if desired, from the system through line HA. The product coming withinthe motor fuel boiling range is removed through line I8. Any higherboiling material such as tar that may be formed in the system is removedfrom fractionation unit I6 through line 19. Any catalyst that may becarried over into fractionation unit II; from separatorfig is removedthrough lines BI and at least a portion of this catalyst material may berecycled through lines 8|, 81 and 54 to reactor 53 or to reactor 62 byway of lines BI, 81 and 63, Also, at least a portion of the catalyst maybe withdrawn from line BI and introduced into catalyst purification unit86 by way of lines 82 and I2. The used catalyst which is introduced intocatalyst purification unit 88 from separators 57 and B9 and fromfractionation unit '16 is purified and returned to the system by way ofline 81. If desired, at least a portion of the purified catalyst may beremoved from the system through line 88.

Referring to Figure 3 of the drawing, a hydrocarbon suitable forcracking to produce ethylene, for example ethane, is introduced throughline Illi to cracking unit I92 where it is cracked under appropriateconditions to produce ethylene. The reaction mixture effluent fromcracking unit 32 is passed through line I03 to ethylene recovery unit wewhere the ethylene is absorbed under suitable conditions of temperatureand pressure in isobutane which is introduced into the ethylene recoveryunit we through line we. The light materials, such as methane andhydrogen, are removed from the ethylene recovery unit I84 through lineIE1 and the materials heavier than isobutane are removed through lineI023. The isobutane which contains the ethylene is removed from ethylenerecovery unit I84 and is passed through line it?) to reactor III. Acatalyst, such as aluminum chloride, preferably dissolved in an aluminumchloride-hydrocarbon complex, is introduced into reactor III by Way ofline II 2. The contents of reactor I I I are maintained underappropriate alkylation conditions and are mixed by any suitable meansnot shown. The reaction mixture effluent from reactor lII passes throughline M3 to separator II i where it is separated by gravity into acatalyst phase and a hydrocarbon phase. The catalyst phase is removedthrough line IIS and recycled to reactor III through lines II '1 and H2.However, at least a portion of the catalyst may be'removed from thesystem through line H5 for purification or use elsewhere, if desired.The hydrocarbon phase rom separator H4 passes through line II8 toreactor IZl. An easily alkylatable cyclic material, such as benzene, isintroduced into reactor it! by way of lines H9 and IIS. Aluminumchloride catalyst, preferably dissolved in an aluminumchloride-hydrocrabon complex, is introduced into reactor I2I throughline I22. The contents of reactor 52; are maintained under appropriatealkylating conditions and are mixed by any suitable means not shown. Thereaction mixture ei'rluent material from reactor I2I is passed throughline 223 to separator I24 where it is separated by gravity into acatalyst phase and a hydrocarbon phase. The catalyst phase is withdrawnthrough line I25 and at least a portion passed to a purification systemnot shown or for use in any manner desired; however, at least a portionof the catalyst phase is recycled to reactor I2I by Wayof lines I21 andI22. The hydrocarbon phase from reactor I24 is passed through :23 tofractionation unit I29. A recycle isobutane stream is removed fromfractionation unit we and is recycled to ethylene recovery unit I06through lines iSI and I06. However, a portion of this recycleisobutane-containing stream may be removed from the system through lineI3 IA if desired. Unreacted benzene is romeved through line I32 andreturned to reactor I2I by way of lines H9 and H8. The reaction productfrom isobutane and ethylene which comprises chiefly diisopropy-l isremoved through line IM. Ethyl benzene formed is removed fromfractionating unit I29 through line I36. Any high boiling product may beremoved fromiractionation unit I19 through line I33.

Referring to Figure 4 of the drawing, an alkylatable paraffinhydrocarbon is introduced into the reactor column I53 through line IEI.An alkylating agent, such as an olefin, is introduced into reactorcolumn I53 by way of lines I52 and 553. A suitable alkylation catalyst,such as sulfuric acid, is introduced through line I51 and introducedinto reactor column I 53 at multiple points through lines I55, I58, H59and IBI. The reactor column is maintained under suitable alleyletionconditions wherein the alkylation reaction takes place and the unreactedoriginal paraffin material is taken overhead through line the andremoved from the system if desired, or at least a portion of thisproduct may be recycled through line I64, cooler I60 and line I5i to thereauctor column I53. An easily alkylatable cyclic organic compound, suchas benzene, is introduced into the reactor column I53 through line 62where it is contacted with the catalyst and reaction products of theparaffin-olefin alkylation step. The reaction mixture efiluent ofreactor column I53 is passed through line I53 to separator I65. Anolefin is introduced through line I65 into the reaction mixture eilluentfrom reactor column I53 passing through line I63 before reachingseparator I 66. The total reaction mixture is separated by gravity inseparator 568 into a catalyst phase and a hydrocarbon phase. Thecatalyst phase is recycled to the system through line I67, however atleast a portion may be removed from the system through line I'S'JA andpassed to a purification system not shown or used in any way desired.The hydrocarbon phase is removed from separator I65 through line I68 forfurther fractionation and purification as desired. Reaction column P53is preferably operated at such temperature and. pressure that butanesand lighter hydrocarbons are removed overhead in the vapor phase andcompounds heavier than butane are withdrawn as liquid kettle products.

In the accompanying diagrammatic drawing including Figures 1, 2, 3 and 4reference to some equipment, such as pumps, gauges, and the like whichobviously would be necessary to actually operate the process of myinvention have been intentionally omitted. Only sufiicient equipment hasbeen shown to illustrate the process of the invention and it is intendedthat no undue limitation be read into this invention by reference to thedrawing and discussion thereof.

This invention may be employed in combination with steps other than aparaffin alkylation step. For example, it may be combined with aparail'in-isomerizationstep or a paraffin-disproportionation stepwherein by-products are formed because of the presence of certainelements or radicals inthe catalyst used, such/as halogen or the sulfateradicals The efiiuent of such step is treated substantially ashas beendescribed for parafiin alkylation. The term paraflin-reconstruction maybe considered asbeing generic to paraffin alkylation, paraflinisomerization and paraffin-disproportionation.

Among the advantages provided by this invention by its clean-up actionon any unreacted alkylating agent and on other materials such as organichalogen or organic sulfate compounds are decreased catalyst consumption;decreased expense and labor for removal of undesirable icy-products; andincreasedyield of organic material suitable for use in motor fuels. Theremoval of olefins is desirable when normal butane for example, isremoved from the reaction mixture and is subsequently catalyticallyisomerized to isobutane.

Example I In a continuous operation like that illustrated by Figure 2 ofthe drawing, isobutane is alkylated in the presence of a hydrofluoricacid catalyst with one or more olefins having mainly three to fivecarbon atoms per molecule. In general, substantially conventionalalkylation conditions may be used, such as an isobutane-to-olefin molratio in the feed of approximately 4:1 to :1, a catalyst-to-hydrocarbonvolume ratio of approximately0.5:1 to-2:1, a, temperature ofapproximately 80 to 120 'F., a titratable acidity of approximately 80 to95 weight per cent hydrogen fluoride, a contact time or residence timeof the reaction mixture in the contactor or niixerreactor ofapproximately 5 to 20 minutes, and a pressure adequate to maintain thereaction mixture in' liquid phase. The reaction mixture effluent fromthe contactor is passed to a separator for separation into hydrocarbonand catalyst phases by gravity. The catalyst phase is recycled to theisobutane-alkylation step, but part of it ordinarily is passed,continuously or intermittently, to a catalyst purification or recoverystep, wherein it is subjected to fractional distillation to free it fromdissolved impurities, mainly from heavy unsaturated hydrocarbonscollectively known as acid-soluble oil. The hydrocarbon phase is passedto a lay-product alkylation step, wherein it is mixed-with approximatelyits own volume of hydrofluoric acid and with approximately 2 to 5 percent of its own volume of refinery blending benzene having an A. P. I.gravity of approximately 30.5" and an A. S. T. M. distillation range forthe first 95 per cent evaporated of approximately-167 to 177 F., whichindicate a high content of benzene. This blending benzene is so calledbecause of earlier utilization for blending with alkylate and othermotor-fuel ingredients to form a high-quality aviation gasoline.Ordinary technical benzene, such as that derived from coal or frompetroleum hydrocarbons byaromatization or the like may be substitutedfor the blending benzene. The mixing and other conditions in theby-product-alkylation step are substantially like the correspondingconditions in the paraffin-alkylation step. The reaction mixture is thenpassed to a third or final alkylation step, wherein it is mixed with anolefin, preferably ethylene-free and further preferably propylene,whichis added in a proportion at least equimolecular' with respect tothe unconsumed benzene in the reaction mixture and preferably slightlyinexcess. The conditions in this final alkylation step are gener- 10ally similar to those in the preceding alkylation steps except that thecontact time is ordinarily shorter, approximately '1- to 10 minutes, incorrespondence with the relatively high reactivity of the benzene,whichappears to outweigh its relatively low concentration. Any excessolefin appears to be substantially consumed without undergoingpolymerization, apparently mostly in secondary or further alkylation ofbenzene, accom panied by some primaryalkylation of isobutane.

As soon as the added olefin. is consumed, the reaction mixture is passedto a settler for separation into hydrocarbon and catalyst phases bygravity. The catalyst phase is recycled to the by-product-alkylationstep; ordinarily little of this catalyst phase needs tofbe removed forpurification. The hydrccarbonphase is passed to fractionation means forfractional distillation into various fractions. A minor low-boilingazeotropic fraction of hydrofluoric acid and isobutane may be obtainedand may be passedto the byproduct-alkylation step, but ordinarily thislow-. boiling material is included with a major fraction ofunreactedisobutane, which is recycled to the paraffin-alkylation step.A. motor-fuel fraction is withdrawn as the main product of the process;it comprises both isoparafiinic and aromatic alkylates, includingcumene, and has a desirably high quality for use in aviation gasoline. Aminor fraction of high-boiling hydrocarbons is withdrawn and maybesubjected, if desired, to cracking for production of olefins.

Example II E':cample III A gaseous stream having approximately 12 molpercent ethane and 88' mol' per centpropane is subjected to cracking,yielding an eilluent having the following approximate composition, inmol 7 per cent: hydrogen, 16; methane. 30; ethylene, 24; ethane, 7;propylene,'11; propane, 11; butane and heavier, 1. 'This eflluent iscooled and is compressed to about 800 p. s. i. After being again cooled,it is subjected to absorption at approximately 40 to F. by mineral sealoil, Which removes most of the propylene and heavier hydrocarbons..Amo'n'g'these heavier hydrocarbons is a small proportion of aromaticoils formed in the cracking step; if desired, these may be suitablyrecovered and subsequently used as part of the benzeneinthebenzene-alkylation step. The unabsorbed gas has thefollowingapproximate composition, in mol per cent: hydrogen, 25;methane, 52; ethylene, 17 ethane, 5; heavier, 1. This gas ispassed to anethylene recovery column forremoval. of hydrogenand methane and forabsorption of ethylene and heavier hydrocarbons by liquid; isobutane ata pressure of approximately 500' p. s. i. and a kettle temperature ofapproximately 230. F. The ethylene-de nuded gas has approximately 32 and65 mol per cent of hydrogen and methane,-respectively,"with 11 generallyless than-- 3 I'nol percent of heavier hydrocarbons. The solution 'ofethylene in isobutane is passedt'o' a'first aluminum chloride-catalyzedalkylation zone, in which alkylation of isobutane with ethylene to formdiisopropyl as the main product is carried out under such conditionsthat the yield of diisopropyl based on ethylene reacted in this step isa maximum, being usually approximately zz to 2.4 pounds of diisopropylper pound of ethylene reacted. The conditions are interdependent to somedegree and may vary somewhat, but the following may be taken as fairlytypical: isobutane-to-ethylene mol ratio, approximately 4 ;1 to 6:1;volume ratio of hydrocarbon phase to catalyst phase, approximately 2:1to 3:1; temperature, approximately 100 to 136 F. viscosityof catalyst,approximately 200 to 400 centistokes at 100 F.;resid ence time inreactor, approximately 10 to 20- minutes. The catalyst phase, whichcomprises aluminum chloride-hydrocarbon compounds or complexes ofincompletely understood; nature, is maintained at the activity necessaryto 'efiect conversion of ap proximately 90 to 94 per cent of theethylene introduced by addition of aluminum chloride and/or hydrogenchloride or equivalent. promoter and by withdrawing some of the catalystphase for purification or" recovery of the aluminum chloride. When theethylene conversion reaches approximately 90- to 94 percent, thereaction mixture is passed, toe. separator system. The separatedcatalyst phase is returned to the reactor or is removed fpr recovery ofaluminum chloride. The hydrocarbon phase is passed to a second aluminumchloride-catalyzed alkylation zone, to which is added also benzeneapproxi-. mately 2 to'6 times in molecular excess of the unreactedethylene. In this zone the ethylene is substantiallycompletely consumedin alkylation of benzene to ethylbenzene. Some polyethylated benzene,mostly diethylbenzene, is also, formed, especially when the ratio ofbenzene to ethylene is relatively low; inaddition. a small proportion ofalkylated benzene other than ethylated benzene is formed as a result ofminor side reactions, which are advantageous in that they decrease thecontent of organic chlorine. Although the catalyst used ii -this:benzeneelkylation step is substantially identical when I fresh: to. thatintroduced into thezisobutane-allrylation step, being prepared forexample, by mixing approximately '7 to 10 parts-by weightof kerosene and1 part of anhydrous aluminum chloride and some hydrogen chloride at, 150to 200 F. for Otto-2.5 hours,

it is not permitted to enter the isobutane-alkylation zone because itacquires a content of henzone. which; would compete with the isohutanefor the ethylene. Consequently, when the reaction between ethylene andbenzene. in the henzene-alkylction-zone'is completed, the reactionmixture is; passed: to. a. second settling system which is distinct andseparate from the settling system following the isobutane-alkylatiorizone. The catalyst phase is recycled from the settling system to thebenzene-alkylation zone or is removedfor purification and; recovery ofaluminum chloride. The hydrocarbon phase is passed to afractionationisystem for separatiorr'into various hydrocarbonf;ractions.'. Ethane. and V propane maybe recycledtothe cracking unitfor formation r ethylene... Isobntane is re y l d to t eethylene-recovery unit, for. use as absorbent for, ethylene. Motor-fuelhydrocarbons may be withdrawn as a single fraction, or they may befractionated to recover specific hydrocarbons; for example,unreacted'benzenefmay be recovered as a separate fraction and may berecycled to the benzene-alkylation zone. Ordinarily, the ethylbenzene isobtained in this way as a separate fraction and is passed to furtherprocessing steps for ultimate utilization as styrene in the manufactureof synthetic rubber, but if desired it may be utilized together with thediisopropyl and other products of the process as a motor-fuelingredient. A small proportion of products heavier than motor fuel iswithdrawn as a tarry byproduct of the process.

It is to be understoodthat this invention should not be unnecessarilylimited to the above discussion and description and that modificationsand variations may be made-without departing substantially from theinventionor from the scope of the claims.

I claim:

1. An improved, parafiin alkylation process which comprisesreacting analkylatable parafiin and an olefin in a first alkylation zone maintainedunder alkylation conditions in the presence of an alkylation catalyst;reacting a resulting reaction mixture effluent from said firstalkylation zone with an alkylatable cyclic organic compound in asecondalkylation zone maintained under alkylation conditions; reacting aresulting reaction mixture efiluent from, said second alkylation zonewith, an olefin in athird alkylation zone maintained under alkylation,conditions, and removing .from a. resulting, reaction efiiuent ahydrocarbon fraction boiling within the motor fuel boiling range as aproduct of the process.

2. An improved parafiin alkylation process which comprises reacting anisoparafiinwith an olefin in a first alkylation' zone maintained underalkylation conditions in the. presence of an alkylation catalystproducing an alkylate containing undesirablereaction lay-productcompounds; contacting a resulting reaction mixture efiluent from saidfirst alkylation zone with an easily alkylatable cyclic organic compoundin amount stoichiometrically greater than the amount of said undesirableby-product compounds contained therein in a second reaction zonemaintained under alkylation conditions such that. saidundesirableby-product compounds react. with a portion of said cyclic organiccompound; reacting a resulting reaction mixture eflluent from saidsecond alkylation zone with an olefin in amount stoichiometricallyequivalent to the amount of unreacted cyclic organic compound containedtherein in a third alkylation zone maintained underalkylationrconditions such thatsaid olefin reacts with unreacted cyclicorganic compound, and removing from, a resulting reaction effluent ahydrocarbon fraction boiling within the motor fuel boiling range as aproduct of the D 3. The process ofjclaim 2 wherein said alkylationcatalyst is anhydrous hydrofluoric acid.

4. The process of claim 2-wherein said alkylation. catalyst isfsulfuri'cacid.

5. The process of claim 2 wherein said alkylation catalyst is analuminum chloride-hydrocarbon complex- 6. The process of claim 2.whereinvsaid easily alkylatable cyclic organic compound is benzene.

7. The process of claim 2 wherein said cyclic organic compound isfuran.

8. The process of claim 2 whereinv said isoparafiin is isobutane.

9. The process of claim 2 V wherein said. olefin is butene.

10. An alkylation process which comprises reacting isobutane withbutenes in a first alkylation zone maintained under alkylationconditions in the presence of hydrofluoric acid as an alkylationcatalyst to produce an'alkylate containing organic fluorine compounds;contacting a resulting reaction mixture comprising hydrocarbons andcatalyst eflluent from said first alkylation zone with an alkylatablecyclic organic compound, in amount stoichiometrically in excess of theamount of organic fluorine compounds present in said efiluent, in asecond alkylation zone maintained under alkylation conditions such thata portion of said cyclic organic compound reacts with said organicfluorine compounds; contacting a resulting reaction mixture comprisinghydrocarbons and catalyst effluent from said second alkylation zone withan olefin in amount at least stoichiometrically equivalent to the amountof unreacted cyclic organic compound contained therein in a thirdalkylation zone maintained under alkylation conditions whereby saidolefin reacts with said unreacted cyclic organic compound; passing aresulting reaction mixture eiiiuent from said third alkylation zone to aseparation zone where it is separated into a hydrofluoric acid catalystphase and hydrocarbon phase; recycling at least a portion of saidcatalyst phase to said first alkylation zone; passing said hydrocarbonphase to a fractionation zone and removing therefrom a hydrocarbonfraction boiling within the motor fuel boiling range as a product of theprocess.

11. An improved paraifin alkylation process which comprises reacting anisoparaifin with an olefin in a, first alkylation zone maintained underalkylation conditions in the presence of an alkylation catalystproducing an alkylate containing undesirable reaction by-productcompounds; treating a resulting hydrocarbon phase from said firstalkylatio-n zone with an easily alkylatable cyclic organic compound inan amount stoichiometrically in excess of the amount of the undesirablereaction by-product compounds contained in said alkylate containinghydrocarbon phase in a second alkylation zone maintained underalkylation conditions in the presence of a fluid alkylation catalystsuch that a portion of said cyclic organic compound reacts with saidundesirable by-product compounds; treating a reaction mixture efiiuentcomprising hydrocarbcns and fluid catalyst from said second alkylationzone with an olefin in an amount stoichiometrically equivalent to theamount of unreacted I cyclic organic compound in a third alkylation zonemaintained under alkylation conditions such that said unreacted cycliccompound reacts with said olefin; passing a resulting reaction mixtureefliuent comprising hydrocarbons and catalyst from said third alkylationzone to a separation zone; separating said reaction mixture into acatalyst phase and a hydrocarbon phase; returning at least a portion ofsaid catalyst phase from said separation zone to said second alkylationzone, and recovering from the resulting hydrocarbon phase a fractionboiling in the motor fuel boiling range as a product of the process.

12. An improved alkylation process for the production of diisopropylwhich comprises reacting an isobutane-ethylene mixture in the presenceof a halogen-containing fluid alkylation catalyst in a first alkylationzone producing an alkylate containing undesirable reaction byproductcompounds; treating a resulting alkylate-containing hydrocarbon phasewith benzene in a second alkylation zone maintained under alkylationconditions in the presence of a halogen-containing alkylation catalystsuch that the benzene reacts with said undesirable by-product compounds;passing a resulting reaction mixture efiiuent from said secondalkylation zone together with an added olefin to a third alkylation zonemaintained under alkylation conditions, and passing a resulting reactionmixture efiiuent from said third alkylation zone to a separation zonewhere it is allowed to separate into a catalyst phase and a hydrocarbonphase and separating from said hydrocarbon phase a fraction containingdiisopropyl as a product of the process.

13. An improved paraffin alkylation process which comprises reacting anisoparafiin with an olefin in an alkylation zone maintained underalkylation conditions in the presence of a fluid alkylation catalystproducing an alkylate containing undesirable reaction by-productcompounds; introducing said catalyst into said alkylation zone atmultiple points intermediate the upper and lower portions of saidalkylation zone; withdrawing from upper portion of said alkylation zoneunreacted paraflinic and olefinic materials; treating a resultingreaction mixture comprising alkylate and catalyst with an alkylatablecyclic organic compound in amount stoichiometrically in excess of theamount of undesirable reaction by-products contained in said reactionmixture in a lower portion of said alkylation zone under conditions suchthat said cyclic organic compound reacts with said undesirable reactionby-product compounds; treating a resulting reaction mixture effluentcomprising hydrocarbons and catalyst with an olefin in amountsubstantially stoichiometrically equavalent to the unreacted cyclicorganic compound contained in said resulting reaction mixture efiluent;introducing a resulting reaction mixture comprising hydrocarbons andcatalyst into a separation zone where said resulting reaction mixture isseparated into a catalyst phase and a hydrocarbon phase, and withdrawingsaid hydrocarbon phase as a product of the process.

14. An improved paraflin reconstruction process which comprisescontacting a paraffin in a first zone with a fluid parafiinreconstruction catalyst to produce a reconstructed parafiin andundesirable reaction by-product compounds, contacting a resultingreaction mixture eiiluent from said first zone with an easilyalkylatable cyclic organic compound in amount stoichiometrically greaterthan the amount of said undesirable byproduct compounds containedtherein in a second reaction zone maintained under alkylation conditionssuch that said undesirable icy-product compounds react with a portion ofsaid cyclic organic compound; reacting a resulting reaction mixtureefiluent from said second reaction zone with an olefin in amountstoichiometrically equivalent to the amount of unreacted cyclic organiccompound contained therein in a third reaction zone maintained underalkylation conditions such that said olefin reacts with unreacted cyclicorganic compound, and removing from a resulting reaction effluent ahydrocarbon fraction boiling within the motor fuel boiling range as aproduct of the process.

15. The process of claim 1 wherein the cyclic organic compound has atleast two conjugated double bonds in the ring.

16. The process of claim 1 wherein the third 153-53 16??? alk lation'step' is eefiectewrwith ,a substantially REFERENGES CIT-EDWL-etmiene'free 018ml The following-references are-0f r'ecord in the" 17.'The process..-nf claim 16 wherein the ethylfil of -=-p 1-. cane-freeolefin is propylene. s

lfiJTheprocess of claim 12 wherein the cat- 5 UNITmSTATESiPA'IENTS alystin the first alkylation zone is an aluminum Number" N m D techloride-hydrocarbon complex and. the zone is Mummy operated to giveanrethylene conversion of 90- 54% and in which-pmcess ethyl benzene isre- 10 covered.

2,409,090" Wan-(meme: alt- Oct. 8, 1946 M ARY AN R MATUSZAK. 2,418,146'r Uphamcr'. April, 1947 'D8CZT15, 1942' Chnicek 1 0015.17, 1944" Freyeinuwfiun Mar. 27,1945" 2,432,482. IVISibHsZflk: Decfi9, 1947'

